ANTLR grammar for Java 14 features

While Java 12, 13 and 14 brought some much-anticipated features, Checkstyle users have had to ignore warnings about this code since we don’t support it. We need to update our ANTLR grammar to support new features like text blocks that replace raw string literals and switch expression enhancement. We should also add support for two important preview features; pattern matching for instanceof and records. This project will be a great way to learn more deeply these new Java features while implementing grammar and code that can be utilized by other open-source projects.